1. Field of the Invention
This invention relates to methods of stretch treating every individual fiber of any type of staple fiber or any type of continuous filament fiber, natural or man-made, that is in a strand or strands of substantial uniform thickness. By substantially stretching while simultaneously substantially twisting every individual fiber in such strand or strands in precisely the correct relative amounts. Whereby, such individual fiber's net strength properties gain, and other desireable quality characteristics improvement, as well as their individual fiber and output strand or strands continuous cross-sectional uniformity, are substantially enhanced for their greater utility, as are fabrics and other products produced from such treated fiber.
All the individual fiber within such strand or strands are inherently and effectively captured and stretch processed such that few if any of such fiber can escape effective and uniform treatment. This is achieved with only the simple continuous and simultaneous application of a single dynamic but substantial stretching stress, and a single dynamic but substantial twisting force in precisely the correct relative amounts. The representative devices described herein for an explanation of the present invention's methods' individual fiber stretch processing treatments are relatively simple to explain. However, the explanation of occurrences within such strand or strands, and in particular within each individual fiber, is complex.
When a multiplicity of fiber are being effectively and uniformly stretch processed, each individual fiber within such strand or strands is subjected to substantial torquing, compressing, and stretching forces. Such forces are dynamically transmitted through every individual fiber from one of its ends to its other (staple), or from one stretching point to the other (continuous filament). And, simultaneously transmitted from every individual fiber to its adjacent fiber with which it is in contact, through precisely controlled induced cohesion between them, derived from each of their surface frictional characteristics and compressed contacts. Then, with the prevention of the fiber strand or strands drafting to the maximum practical extent, by generating precisely the correct substantial amount of induced cohesion that is required, every individual fiber is effectively and uniformly stretch processed, rather than being drafted. The individual fibers are stretch processed, but the fiber strand or strands are essentially not drafted. Every individual fiber's internal molecular structure is oriented in the direction of its fiber axis for its substantial strength properties gain, and its desirable quality characteristics improvement.
It is imperative that such fiber in such strand or strands be simultaneously stretched and twisted in precisely the correct relative amounts, to the extent that is practical. If the ratio of twist to stretch is too great (too much induced fiber cohesion) there is too little fiber creep or fiber length increase take-up allowed, and most effective and uniform fiber stretch processing is prevented. If such ratio is too small (too little induced fiber cohesion) there is too much fiber slippage or drafting allowed, and ineffective and irregular fiber stretch processing results.
The substantial stretching against twist treating of any type of staple fiber in precisely the correct amounts using the present invention methods almost entirely prevents its drafting. The primary purpose of the present invention is maximum effective and uniform stretch processing of every individual fiber and not desirable drafting of the strand or strands. The pulling forces are concentrated on stretching the individual fiber while taking up their increase in length and prevented from being wasted in their drafting. Desirable drafting against twist deters effective stretch processing, as substantial stretching against twist of the present invention methods deters desirable drafting.
Maximum effective stretch processing of individual fiber requires relatively, compared to desirable drafting against twist, a substantial amount of stretching stress to just barely overcome the simultaneously applied substantial compressive induced cohesion resistance of the twisting treatment. The stretching forces must just barely overcome the induced cohesion for just the right amount of increased fiber length take-up, without their substantial breakage.
In normal drafting against twist processing of staple fiber where the goal is for maximum effective and uniform drafting of the strand or strands of fiber, and not its individual fiber's effective and uniform stretch processing, a relatively small amount of pulling or drafting force and a relatively small amount of simultaneous twisting is required. The resulting effect is relatively little individual staple fiber resistance to its being pulled or drafted along, among and by its adjoining fibers, but just enough resistance due to the relatively little twist injected for controlled fiber distribution with its adequate slippage. In drafting against twist processing the individual staple fibers are subjected to relatively little or no stretching force, but to small frictional slipping forces along the entire length of every individual staple fiber. Therefore, very little if any measurable effective or uniform individual stretch processing is achieved. Existing drafting against twist art methods are used for maximum effective and uniform desirable drafting of the strand or strands of staple fiber, not the stretching of its individual fibers.
Continuous filament fiber consist of individual fiber that is continuous in its length, so it does not lend itself to drafting or drafting against twist. However, continuous filament fiber has been discovered to be compatible with these present invention methods of stretching against twist for its maximum effective stretch processing in the absence of drafting. Similar to staple fiber using these present invention methods, the pulling stress is concentrated on stretching continuous filament fiber while taking up their increase in length and preventing substantial breakage of individual continuous filament fiber due to excessive take up.
Maximum effective and uniform stretch processing of continuous filament fiber using the present invention methods also requires relatively a substantial amount of stretching stress to just barely overcome the simultaneously generated compressive induced cohesion resistance of its relatively substantial twisting treatment without substantial fiber breakage. These present invention methods substantially improves the uniformity of such filament fiber stretch processing throughout its continuous length as compared with other continuous filament fiber stretch processing methods that do not fully utilize the stretching against twist method as herein provided.
It is known that the strength properties and utility of most substantially uniform filament fibers of continuous length can be improved by first subjecting the initially extruded fiber to a stretching process in which its internal structure molecules are oriented in the direction of its filament axis. Such stretched filament fiber using heretofore available stretching processes often show irregular fluctuations in thickness or its cross-sectional area throughout its continuous length. The thicker portions of the filament having been stretched to a lesser degree than the thinner portions, results in irregularities in its count (weight per unit length) throughout its length. Such irregularities and loss of its original uniformity is further aggravated as the degree of stretching is increased, or a plurality of stretchings are attempted.
Woven or knitted fabrics produced from such filament fiber show unevenness in the weave or stitch construction. Since moreover the portions stretched to a lesser degree absorb a lesser quantity of dye when such woven or knitted fabrics are dyed than the portions which are more highly stretched, the textiles thus obtained are often unsuitable for use.
Besides these defects, crimping phenomena are found in such stretched filament fiber when subsequently subjected to shrinkage processing, where adjacent capillary filaments at the same portion of such filament also have a different degree of shrinkage due to the different degree of stretching. This causes the capillary filaments which shrink to a higher degree in the shrinkage process to displace those capillary filaments which shrink to a lesser degree, whereby a shrinkage crimped fiber with looped capillary filaments is obtained. This may be of advantage for specific use, but in general such a shrinkage processed filament fiber is required to have a smooth surface.
The present invention methods essentially prevents these defects and irregularities, and allows the retention of the filament fiber's original input substantial uniformity. In operation the present invention methods' twisting and stretching forces are evenly distributed throughout every filament or capillary filament fiber and each of its internal molecular structures. Simultaneously it evenly transmits such forces from every filament or capillary filament fiber to all of its other adjacent such fiber with which it is in compressed cohesive contact where multiple fiber strands are being simultaneously processed.
The present invention methods use substantially improve filament fiber (including natural filament fiber like silk) stretch processing uniformity throughout its continuous length, while simultaneously improving their stretch processing effectiveness (as can be done with man-made staple fiber as well as natural) where such fiber has remaining stretch processing improvement potential that has not been fully utilized through previous stretch processing.
Series multiple stretching of filament fiber using the present invention offers substantial improvement in their maximum strength properties (due to using series incremental treating rather than single total treating) while at least retaining their original input substantial uniformity. This has not been practical heretofore since it is physically more difficult to accomplish series multiple stretching utilizing heretofore available filament fiber stretch processing methods and devices. The primary limitation in utilizing such heretofore available stretch processing methods and devices for series multiple stretchings is that multiple treating has heretofore inherently aggravated unevenness and generated unacceptable irregularities in count, dyeing, and shrink crimping uniformity, with substantial loss of the input fiber's original substantial uniformity.
Fiber strength properties are similar to metal wire strength properties in that when either are dry ambient stretched beyond their elastic limit or yield point, but not to their rupture or ultimate strength point, they can never return to their original shape or dimensions and are changed to another configuration when the stretching stress is removed, even though they will spring back somewhat from their fully deformed state. When this is done, both their yield point and rupture point advances to a higher level of stretching stress value in relation to their original level, and such points advance in relation to the degree of stretching to which they have been subjected.
When a subsequent or successive dry ambient stretch processing treatment of such prior treated fiber or metal wire is imposed on either of them, beyond their new yield point but less than their new rupture point, both there yield point and rupture point are again advanced to a higher level. As long as the rupture point is not reached, several multiple or successive dry ambient stretchings of such fiber or metal wire are possible, until finally their rupture point cannot be advanced any more without rupture, thereby substantially improving their strength properties and other desireable quality characteristics. The smaller the incremental advancement of these points with smaller amounts of stretching stress, and correspondingly the more multiple or successive treatments, the higher such advancement can be achieved for maximum results. However, there is a practical limit to the number of incremental treatments that can be imposed. The time required and cost incurred can exceed the stretch processing improvements value gained.
The number of ambient metal wire multiple stretch processing treatments normally utilized is dependent on the kind and alloy being stretch processed, and may vary normally from 4 to 12. The wide variations of all types of fiber in their composition and characteristics also cause a wide variation in the optimum number of multiple or successive stretch processing treatments that should be utilized.
In effectively and uniformly stretch processing any type of fiber utilizing any method, there are four primary factors that must be taken into consideration to achieve maximum practical effectiveness and uniformity.
First, every individual fiber regardless of its length must be stretched uniformly throughout its entire length to the maximum practical extent. In the treatment of staple fiber every individual fiber must be stretch processed from one of its ends to its other, while continuous filament fiber must be stretch processed from one of its chosen stretching points to its other.
Second, the correct duration of continuously applied stretching stress during each fiber's stretch processing treatment provides substantially more effective and uniform individual fiber stretch processing, than quick tugs of short duration.
Third, continuous series or discontinuous individual multiple stretch processing treatments provides substantially more effective and uniform individual fiber stretch processing, than single stretch processing treatment.
Fourth, the correct stress relaxation time between multiple stretch processing treatments provides substantially more effective and uniform individual fiber stretch processing, than no stress relaxation between such treatments.
2. Description of the Related Art
An analysis of drafting against twist processing patents has been conducted in search of prior art pertaining to this present invention, i.e.; Millardi et al U.S. Pat. No. 4,735,041 4/1988; Althof U.S. Pat. No. 3,151,438 10/1964; Hadwich U.S. Pat. No. 2,688,837 9/1954; Reinicke U.S. Pat. No. 2,608,817 9/1952; Harris U.S. Pat. No. 2,143,876 1/1939; Harris U.S. Pat. No. 1,922,950 8/1933; Harris U.S. Pat. No. 1,922,949 8/1933. Each of these patent's specifications refers many times to the drafting of a strand or strands of staple fiber, but never to the physical stretching of any individual staple or continuous filament fiber. If desirable drafting occurs during such processing, effective stretch processing is prevented. The embodiment devices related in these patents are incapable of using, withstanding or transmitting the substantial fiber stretching and simultaneously applied twisting forces that are required for maximum effective and uniform stretching against twist processing of the present invention methods of any type of staple or continuous filament fiber. It apparently was not obvious to these or any others skilled in the art, that a stronger and more durable twisting device could be used for converting the drafting against twist processing to that of stretching against twist.
Drafting against twist processing of staple fiber has been used to produce textiles perhaps for over 5,000 years, but apparently has always been used for effective desirable drafting and never considered for conversion into effective and uniform stretch processing of individual fiber. Stretching against twist processing of any fiber, staple or continuous filament, natural or man-made, as used by the present invention methods is apparently unique in the art to which its subject matter pertains, and its discovery has substantial commercial potential.
Most continuous filament fiber produced is stretch processed by at least one patented method to improve its strength properties, although the uniformity of such filament fiber stretch processing throughout its continuous length is not as good as desired. Many patents were found pertaining to the stretch processing of such fiber between two stretching points. However, none were found that substantially stretches every individual filament fiber while simultaneously substantially twisting every strand or strands in precisely the correct relative amounts, substantially to improve the uniformity of such filament fiber stretch processing treatment throughout its continuous length, as can be accomplished through the use of the present invention methods.
Apparently, for probably over 5,000 years no such thought or reasoning regarding effectively stretch processing any individual staple or continuous filament fiber against twist for its improvement occurred to anyone. There is no evidence known to the applicant of any achievement of effective stretch processing of any individual fiber against twist prior to this present invention. Not only is there apparently no directly applicable prior art, but the new art of this present invention is not commonly or widely known, if it is known at all, in the textile, or any other, field of activity. The differences between the subject matter sought here to be patented and the somewhat related prior art are such that the subject matter as a whole apparently was not obvious, at the time any prior invention was made, to any person having ordinary skill in the art to which said subject matter pertains. Such prior inventors or those skilled in the art were apparently totally engrossed with the subject matter of desirable drafting of a strand or strands of fibers and not their obscure individual fiber stretch processing, or conversion potentials of drafting against twist processing to that of stretching against twist. Their application devices were apparently never intended for the rugged applications of effective and uniform stretching against twist processing of individual fiber of the present invention.
In search of prior art pertaining to this present invention, other than drafting against twist (7 related patents discussed above) and filament fiber stretch processing methods, the only patent that could be found that relates to the physical stretching of individual staple fiber is; Cerny U.S. Pat. No. 2,387,058 10/1945; "Treatment of Cotton Fibers"; patent classification 57-310 Textiles, Spinning, Twisting and Twining--Apparatus and Process; with stretching. This method specifically rejects any twisting of the staple fibers, and specifically stipulates that the processed bundle or strand of cotton staple fibers be prestressed with the distance between its two stretching points set less than the length of the cotton fibers, to stretch the individual cotton fibers without breaking them. The present invention methods require substantial stretching while simultaneously substantially twisting every individual staple fiber in precisely the correct relative amounts, with the distance between its two stretching points more (rather than less) than the length of any staple fiber being processed without substantial breakage.
A thorough analysis of U.S. Pat. No. 2,387,058 Oct. 1945 Cerny was conducted to determine if it contains prior art pertaining to this present invention. To analyze its relative effectiveness in relation to the present invention's effectiveness in stretch processing every individual cotton staple fiber from one of its ends to its other, a standard representative lot of cotton staple fiber to be analyzed as being processed by both methods was first defined.
In summary, this cotton staple fiber stretching method, as described in the published patent document, uses steel grips to stretch small fiber bundles that contained about 1575 parallel fibers and weigh 5 mg., and were carefully cut to be 3/4 inch in length. Such test bundles were cut from cotton having a 11/8 inch standard class stock staple length that had been carded, drawn and combed. The cut bundles were carefully cleaned and hand combed to remove foreign material and to arrange the fibers in an untwisted parallel relation. Such bundles were prepared after and during standard atmosphere conditions exposure. These test bundles were mounted vertically in steel grips with a distance between grips being 3/16 inch making sure that every individual fiber was firmly gripped to prevent any slippage.
Six sets of tests were conducted using the carefully prepared test bundles, and excellent unquestionable test data was obtained. Unfortunately these test results relate only to the 3/16 inch length of cotton fiber that was carefully prepared and fixed between two steel grips. The remainder of the individual cotton fibers that originated from 11/8 inch standard classed stock was either cut away from the carefully prepared bundles or was subjected to the compressive pressure of the steel grips, neither fiber segments of which was stretch processed at all, or entered into the test results. The 3/16 inch cotton fiber length that was treated remained fixed in its steel grips while it was subsequently tested.
None of the 3/16 inch treated fibers were said to have been cut from between the steel grips and used in any way to produce effectively stretch processed yarn or fabric or any other textile product to determine the useability of such 100% effectively stretch process treated cotton staple fiber. Likewise there were no 11/8 inch standard class stock staple fibers said to be fixed in these steel grips allowing 3/16 inch of their length to be effectively stretch processed and then released from its steel grips in its full length to then be processed into yarn or fabric or any other textile product to determine the useability of such staple fiber that was only 3/16 inch treated (about 16% effectively stretch processed) fiber. However, the results of these six sets of stretch processing tests on only 3/16 inch of the individual cotton staple fibers that were tested, probably represents what might be expected if the entire length of all such individual fibers were stretch processed according to the tests but throughout each of their entire length.
Similar laboratory test to these have been conducted for over 50 years in many areas of the world with similar results. Recently extensive testing was conducted to determine the useability potential of the present invention method of stretch processing any fiber, including cotton. Here the stretch processed cotton staple fiber test results closely correspond to the test results of the above related six sets of cotton staple fiber stretch process testing.
After over 50 years of such testing it is conclusive that any fiber, natural or man-made, can be substantially improved through its appropriate stretch processing. Man-made continuous filament fiber stretch processing methods and devices have been developed and patented, but with their remaining difficulty of providing uniformity of such filament fiber stretch processing throughout its continuous length. Throughout this half century the necessity of effectively stretch processing natural staple fiber to fully utilize its known potential of substantial improvement has challenged many possible inventors. U.S. Pat. No. 2,387,058 Oct/1945 Cerny was apparently the only one successful in obtaining a methods patent for Treatment of Cotton Fiber.
One of Cerny's patented methods comprises arranging a multiplicity of untwisted cotton fibers in a substantially parallel relation, gripping each of the ends of the individual fibers with force sufficient to prevent slippage when tension is applied thereto, applying tension to the individual fibers sufficient substantially to stretch the individual fibers without effecting breakage thereof while the individual fibers are so gripped and without slippage of the fibers from their gripped position. It is incomprehensible to the applicant that such a laborious process could ever be seriously considered for a commercial activity.
Another of Cerny's patented methods comprises preparing a sliver of substantially uniform thickness and consisting of a multiplicity of untwisted cotton fiber in substantially parallel relation with the staple fiber stretch processing points being spaced apart a distance less than the length of the cotton fiber in the sliver so the ends of the individual cotton fibers in the sliver are simultaneously gripped with substantially equal forces by the two stretching points substantially to stretch the individual cotton fibers within the sliver without breakage thereof whereby to obtain a sliver of substantially the same thickness as the original sliver. In using Cerny's preferred embodiment of this method, a drawing machine type of cotton staple fiber stretch processing device, its productivity should be greater than using steel grips and carefully prepared fiber bundles, but its productivity is inversely proportional to its desired stress duration time, and its maximum practical output is probably only about 11/2 yds/min.
Cotton fiber is available in commercial production quantity only in randomly mixed lengths of individual fibers. For such cotton staple fiber to be arranged in sliver of substantially uniform thickness that is untwisted and in substantially parallel relation utilizing the most practical currently available commercial processing methods and devices, it would have to be carded, drawn and perhaps combed. The randomly mixed lengths of individual fibers in such sliver, to be substantially uniform in thickness, would also have to be randomly distributed along such sliver's processing flow axis. To utilize any of Cerny's patented methods, a staple fiber stretch processing zone between two stretching points must be selected and set to be used that is less than the length of the cotton fibers in such sliver. Any zone distance chosen, 3/16 inch, 2/3 inch or any that is less than the longest fiber being processed, that zone will contain randomly the fiber ends of individual fibers that can not be simultaneously gripped with substantially equal forces by the two stretching points. Therefore, staple fiber stretch processing effectiveness will be reduced.
The thorough analysis of this patent referenced above, clearly shows that in using any staple fiber stretch processing method, every fiber must be effectively stretched from one of its ends to its other for 100% effective stretching. None of the fiber's length can be used for gripping or be outside the gripping points, and the distance between gripping points must be at least as long as every individual fiber being stretched, or the effectiveness of stretch processing such fiber will be correspondingly reduced. Therefore, as long as the staple fiber stretch processing zone is less than the length of the staple fiber being stretch processed, as is required in utilizing Cerny's methods, 100% effective stretch processing is impossible for commercial activity.
This above referenced analysis of Cerny's patented methods also clearly shows that with a single stretch processing treatment passage, only about 54% maximum stretch processing treatment at any production rate is probable, with a maximum desired stress duration time treatment at normal production rate (about 11/2 yds/min) of only about 12% is probable. The production rate of Cerny's preferred embodiment is inversely proportional to its stress duration time, so reduced production could increase stress duration time treatment. However, this is inefficient staple fiber stretch processing. Of greater importance, the resulting effectiveness of the stretch processed cotton staple fiber strength properties improvement is probably unacceptable.
Although most of the individual treated staple fibers are stretch process improved for a portion of their length, they are not stretch process improved at all in the remaining portion of their length. Such fiber's overall stress resistance might not be improved at all, since they might break at their weakest point (within its unstretched portion) when subjected to high stress loads that their effectively stretched portion could withstand.
It is impossible (using Cerny's but not the present invention methods) to stretch the staple fibers that are shorter than the stretch processing zone chosen and set for processing such staple fibers. And, the staple fibers that are longer than such zone are only partially stretched (a portion of their length improved in strength properties, and the remaining portions of their length not improved at all). The staple fibers must always be longer than such zone in using the present invention methods, whereby all staple fibers are near 100% effectively stretch processed.
The published document of Cerny's methods patent relates no way by which the results of the six sets of tests described therein can be commercially accomplished as implied using such methods, except 3/16 inch lengths of cotton staple fiber that are not suitable for commercial use.
In contrast, this present invention method of stretch processing any fiber, staple or continuous filament, or natural or man-made, allows for 100% stretch processing treatment in a single stretch processing treatment passage (although multiple series passes will usually provide better results). It does this while simultaneously it also allows for 100% minimum desired stress duration time treatment without reducing maximum practical production rate (over 50 yds/min) or stretch processing uniformity. This production rate is all that is required for integration compatibility with yarn forming methods and devices with the highest practical production rates without compromise. Each fiber, regardless of its individual fiber length, can be stretch processed effectively and uniformly throughout its entire length, from one of its ends to its other (staple fiber), or from one of its stretching points to its other (continuous filament fiber). The stretch processing zone distance only has to be, greater than the longest fiber (staple fiber), and the desired distance to obtain the desired degree of stretch processing uniformity throughout such distance (continuous filament fiber or staple fiber). Desired stress duration time can be obtained without reduction of production or uniformity by merely increasing the distance between stretching points. Stretch processing zone distance can be over 100 inches if desired without compromising fiber stretch processing effectiveness or uniformity.